1. Field of the Invention
This invention relates to antennas, and, more particularly, to a nondirectional, compact and rugged half-wave dipole antenna.
2. Description of the Prior Art
The most fundemental antenna is the dipole, or half-wave dipole antenna. Dipole antennas employ a linear conductor disposed substantially parallel to the ground which is driven from its center so that its ends are permitted to resonate. There are a wide variety of modifications to this structure including a single conductor folded to form multiple sections which are parallel to each other and ground, and parallel matching conductors which are driven in various arrangements. The sensitivity of such antennas can be increased either by increasing the collector area, by arranging the dipole antenna and in an array, or by providing the antenna with reflectors. Any of these alternatives are inconsistent with the requirements of compactness which is demanded in a mobile antenna, and the later alternatives increase the directivity of the antenna pattern which is usually undesirable for mobile antennas.
One antenna structure which is sufficiently sensitive and compact to be advantageously employed as a mobile antenna is the loop or halo antenna. However, such loop antennas are somewhat directional so that they are not particularly suited to mobile operation since the orientation of the vehicle with respect to the signal source results in intermittent reception.